Lookout, a company that offers security services for a number of smartphones, is releasing the results of its Mobile Threat Report. The report is based on threat and security data from Lookout’s Mobile Threat Network, which includes data collected from more than 700 thousand apps and 10 million devices worldwide. You can access the full report here.

Lookout’s main finding is that mobile malware has increased significantly, with Android users two-and-a-half times as likely to encounter malware today than just six months ago. Lookout estimates that between a half million and one million users were affected by mobile malware in the first half of 2011.

During the first half of 2011, the number of unique apps with malware found on markets and download sites grew from 80 to 400 apps. DroidDream, one of the most popular threats, released more than 80 unique apps to take control of a user’s phone. And GGTracker, a newer malware threat that specifically targets U.S. Android users via premium text message services, has upped its infected app count to 15 apps/

And threats aren’t just receiving malware through apps and app markets. Mobile web-based threats have also emerged as a significant part of the threat landscape with three out of ten mobile users likely to click on an unsafe link, including malicious and phishing links, over the course of a year.

Unfortunately, Lookout says that malware writers are using new techniques to to infect phones. Now some mobile ads aren’t safe as well. Using tactic called Malvertising, writers use mobile ads to direct users to a malicious website that triggers an automatic download of malware.

Basically, now more than ever, smartphone owners need to be cautious about downloading apps from trusted app stores and download sites and clicking on links in the mobile web. Lookout’s own security app can help users combat these issues.

Over the second quarter of 2011 Lookout saw an 85% increase in the number of mobile malware detections across its user base. And ecause of this trend, Lookout’s offerings have been growing fast. In December, the company had 4 million users and has now more than doubled that number, with ten million users. Lookout is currently adding 1 million users per month. And the company just raised $19.5 million in funding from Index Ventures, Accel Partners and Khosla Ventures. Even carriers are starting to take note.